Floating gastrointestinal anchor

ABSTRACT

Apparatus ( 90 ) is provided for use in a stomach of a subject. The apparatus includes a balloon ( 92 ), adapted for placement in the stomach, and an anchor ( 102 ), coupled to the balloon. The anchor is adapted to prevent the balloon from passing into a duodenum of the subject. The apparatus further includes an inflation tube ( 96 ), coupled to the balloon to permit inflation of the balloon, and is adapted to stretch from the stomach to a mouth of the subject to facilitate inflation of the balloon. Other embodiments are also described.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/856,877, filed Apr. 4, 2013, which is a continuation of U.S. patentapplication Ser. No. 13/108,487, filed May 16, 2011, which issued asU.S. Pat. No. 8,430,895 on Apr. 30, 2013, which is a continuation ofU.S. patent application Ser. No. 11/718,795, filed Jul. 9, 2007, whichissued as U.S. Pat. No. 8,430,894 on Apr. 30, 2013, which is a NationalStage entry of PCT/IL07/00398, filed Mar. 28, 2007, which claimspriority to U.S. Provisional Application No. 60/815,624, filed Jun. 21,2006 and U.S. Provisional Application No. 60/787,124, filed Mar. 28,2006, all of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention generally relates to implantable medicalapparatus. Specifically, the present invention relates to apparatus forimplantation in the gastrointestinal tract.

BACKGROUND OF THE INVENTION

Morbid obesity remains an ever-growing problem in the U.S. Varying formsof gastric bypass surgery have developed and have improved over the lastfew decades. Recently, laparoscopic gastric banding has emerged as aless invasive surgical option. However, bariatric surgery is fraughtwith morbidity of up to 20%, with a re-operation rate approaching 25% at3-5 years post-op. Bariatric surgery carries an operative mortality of0.5%. Diet and pharmaceutical alternatives have not been very effective,with a high recidivism rate. Today, the Bioenterics® intragastricballoon (BIB®) (Inamed Corporation, Santa Barbara, Calif., USA) is inuse outside of the U.S., achieving average weight loss of 15 kg and 5point drop in BMI. However, an 8-9% balloon deflation rate has resultedin unwarranted migration leading to obstruction.

PCT Patent Publication WO 06/070361 to Brooks, which is incorporatedherein by reference, describes apparatus for use in a gastrointestinaltract of a subject. The apparatus includes a straightening rod, and aflexible tubular anchor having a distal end and an open proximal end,and sized to fit in the gastrointestinal tract. The anchor comprises amaterial that has an elastic memory which biases the anchor towardsassuming a pre-selected bent configuration. The anchor is shaped so asto define a central core extending from the open proximal end toward thedistal end. The anchor is configured to be straightened from thepre-selected bent configuration by insertion of the straightening rod inthe central core. The apparatus further includes a device coupled to theanchor, selected from the list consisting of: a therapeutic device, anda transmitting device.

US Patent Application Publication 2004/0044357 to Gannoe et al., whichis incorporated herein by reference, describes gastric space occupyingdevices that include a stent configured for deployment in thegastrointestinal tract of a patient, and in particular, for deploymentin the esophagus or the stomach. Secured to the stent is an expandablemember that is adapted to reside within the patient's stomach. Whenexpanded, the expandable member occupies a predefined volume within thepatient's stomach and is further tethered to the deployed stent, therebyretaining or anchoring the expandable member within the stomach. Methodsand systems for the deploying the space occupying devices are alsodescribed.

PCT Publication WO 05/107641, US Patent Application Publication2005/0267596, and US Patent Application Publication 2005/0267595 to Chenet al., which are incorporated herein by reference, describe a gastricballoon that includes a scaffold structure, one or more internalinflatable compartments within the scaffold structure, and one or moreinflatable bladders formed over the space-filling compartment. Thegastric balloon may be deployed transesophageally using a gastroscope,and is inflated in situ, preferably using a combination of liquid andgas inflation media.

PCT Publication WO 05/009288 and US Patent Application Publication2005/0033331 to Burnett et al., which are incorporated herein byreference, describe techniques for facilitating intermittent and/orpartial obstruction of a pyloric valve. Devices described generallyinclude a support portion for preventing the device from passing throughthe pyloric valve, and a tissue engagement portion for contacting tissueadjacent the pyloric valve to obstruct the valve. Some embodiments alsoinclude a positioning member extending from the tissue engagementportion for helping position the device for obstructing the valve. Aretaining member may optionally be included on the distal end of thepositioning member for further maintaining a position of the device inthe stomach. Some embodiments are deliverable into the stomach throughthe esophagus, either by swallowing or through a delivery tube orcatheter. Some embodiments are described as being fully reversible. Someembodiments self-expand within the stomach, while others are inflated orotherwise expanded.

US Patent Application Publication 2005/0055039 to Burnett et al., whichis incorporated herein by reference, describes a device for performingone or more functions in a gastrointestinal tract of a patient, whichincludes an anchoring member and at least one actuator, sensor, orcombination of both coupled with the anchoring device. The anchoringdevice is adapted to maintain at least part of the device within apyloric portion of the patient's stomach and to intermittently engage,without directly attaching to, stomach tissue. Actuators perform anysuitable function, such as transmitting energy to tissue, acting as asleeve to reduce nutrient absorption, occupying space in the stomach,eluting a drug and/or the like. Sensors may be adapted to sense anysuitable patient characteristic within the patient's gastrointestinaltract, such as pH, temperature, bile content, nutrient content, fats,sugars, alcohol, opiates, drugs, analytes, electrolytes and/orhemoglobin.

US Patent Application Publication 2006/0020278 to Burnett et al., whichis incorporated herein by reference, describes methods, devices andsystems which facilitate gastric retention of a variety of therapeuticdevices. Devices generally include a support portion for preventing thedevice from passing through the pyloric valve or esophagus. A retainingmember may optionally be included on the distal end of the positioningmember and is described to maintain a position of the device in thestomach. Some embodiments are deliverable into the stomach through theesophagus, either by swallowing or through a delivery tube or catheter.Some embodiments are fully reversible. Some embodiments self-expandwithin the stomach, while others are inflated or otherwise expanded.

PCT Publication WO 05/094257 to Birk, which is incorporated herein byreference, describes a gastric balloon and method of adding and removingfluid therefrom. The gastric balloon includes a shell, a receiver, and aretractable tubing housed in the receiver and extendable from thestomach of a patient to the mouth of the patient. The shell is inflatedand deflated from outside the body of the patient. The method of addingor removing fluid from the implanted gastric balloon includes steps ofinserting a gastroscopic tool into the stomach of a patient and graspingan end of a retractable tubing housed in a receiver of the gastricballoon. Further steps of the method include withdrawing at least aportion of the retractable tubing from the stomach and out of apatient's mouth and adding or removing fluid from the gastric balloonvia the retractable tubing withdrawn from the patient.

The following patents and patent application publications, which areincorporated herein by reference, may be of interest:

-   U.S. Pat. No. 7,033,384 to Gannoe, et al.-   US Patent Application Publication 2006/0190019 to Gannoe et al.-   US Patent Application Publication 2002/0055757 to Torre et al.-   US Patent Application Publication 2005/0228504 to Demarais-   US Patent Application Publication 2005/0085923 to Levine et al.-   US Patent Application Publication 2005/0192614 to Binmoeller-   US Patent Application Publication 2004/0267378 to Gazi et al.-   U.S. Pat. No. 4,416,267 to Garren et al.-   U.S. Pat. No. 4,925,446 to Garay et al.-   U.S. Pat. No. 5,052,998 to Zimmon-   PCT Publication WO 05/039457 to Paganon et al.-   PCT Publication WO 04/089262 to Paganon-   Canadian Patent Application Publication 2483335 to Byrum et al.-   US Patent Application Publication 2005/0070937 to Jambor et al.-   US Patent Application Publication 20005/004430 to Lee et al.-   PCT Publication WO 04/105622 to Ritchie-   US Patent Application Publication 2004/088008 to Gannoe et al.-   PCT Publication WO 04/014237 to Gannoe et al.-   US Patent Application Publication 2004/093091 to Gannoe et al.-   US Patent Application Publication 2004/059289 to Garza et al.-   PCT Publication WO 03/095015 to Alverdy-   European Patent Application Publication EP 1342458 to Creusy et al.-   US Patent Application Publication 2003/158569 to Wazne-   PCT Publication WO 03/055420 to Lointier et al.-   U.S. Pat. No. 6,656,194 to Gannoe et al.-   US Patent Application Publication 2003/171768 to McGhan-   PCT Publication WO 02/40081 to Bales et al.-   PCT Publication WO 01/66166 to Birk-   PCT Publication WO 98/56321 to Pier et al.-   U.S. Pat. No. 5,234,454 to Bangs-   Canadian Patent Application Publication CA 2068715 to Kuzmak-   U.S. Pat. No. 4,696,288 to Kuzmak et al.-   U.S. Pat. No. 5,129,915 to Cantenys-   U.S. Pat. No. 5,084,061 to Gau et al.-   U.S. Pat. No. 4,908,011 to Jacobsen et al.-   European Patent Application Publication EP 0246999 to Eshel et al.-   PCT Publication WO 87/00034 to Taylor-   U.S. Pat. No. 4,739,758 to Lai et al.-   PCT Publication WO 86/06611 to Kullas et al.-   U.S. Pat. No. 4,694,827 to Weiner et al.-   German Patent Application Publication DE 3540936 to Stricker et al.-   British Patent Application Publication GB 2139902 to Celestin et al.-   Canadian Patent Application Publication CA 1233387 to Garren et al.-   U.S. Pat. No. 4,899,747 to Garren et al.-   German Patent Application Publication DE 3326061 to Woerner-   German Patent Application Publication DE 3310234 to Husfeldt-   Italian Patent IT 1235492 to Frimberger et al.-   U.S. Pat. No. 4,485,805 to Foster-   German Patent Application Publication DE 3227585 to Woerner-   U.S. Pat. No. 4,416,267 to Garren et al.-   U.S. Pat. No. 4,315,509 to Smit-   U.S. Pat. No. 7,004,176 to Lau

The following articles, which are incorporated herein by reference, maybe of interest:

-   Kadakia S C et al., “Esophageal dilation with polyvinyl bougies    using a marked guidewire without the aid of fluoroscopy,” Am J    Gastro 88:1381-86 (1993)-   Fleischer D E et al., “A marked guidewire facilitates esophageal    dilation,” Am J Gastro 84:359-61 (1989)-   Dumon J R et al., “A new method of esophageal dilation using    Savary-Gilliard bougies,” Gastro Endosc 31:379-82 (1985)-   Werth et al., “A safe and quick method for endoscopic retrieval of    multiple gastric foreign bodies using a protective sheath,” Surg    Gynecol Obstet 171(5):419-20 (1990)

SUMMARY OF THE INVENTION

According to one aspect of the invention, a flexible tubular anchorhaving an elastic memory for assuming a pre-selected bent configurationis described for placement in the gastrointestinal tract. The anchorcomprises a distal end and an open proximal end having a central coreextending toward the distal end. When the core receives a straighteningrod therethrough, the anchor is straightened from its pre-selected bentshape.

In accordance with another aspect of the invention, a method ofinserting a flexible tubular anchor in a subject's gastrointestinaltract is described. The anchor has an elastic memory for assuming apre-selected bent shape and has a distal end, an open proximal endhaving a central core extending toward the distal end, a balloon sealedalong a portion of the anchor, an inflation conduit extending from theproximal end to the interior of the balloon, a pushing catheter having abore therethrough axially aligned with the anchor, and a straighteningrod extending through said catheter and the anchor. The method generallycomprises inserting the anchor in its straightened configuration intothe subject's stomach, separating the anchor from the straightening rodthereby allowing the anchor to assume its pre-selected bent shape, andthen inflating the balloon.

In some embodiments of the present invention, a floatinggastrointestinal anchor comprises a flexible tube, which, in its relaxedposition, is shaped so as to define a generally planar base portion, anda proximal portion that projects away from the plane defined by the baseportion, typically in an approximately perpendicular direction. Theanchor further comprises at least two cross-bar elements, the ends ofwhich are positioned in a vicinity of the base portion of the anchor.The cross-bar elements help maintain the shape of the anchor. The anchortypically, but not necessarily, is positioned in an antrum, adjacent tothe pyloric valve, and to some extent interferes with natural antralcontractions, thereby slowing gastric emptying and enhancing thesensation of satiety. The proximal portion of the anchor is typically,but not necessarily, coupled to a device, such as a therapeutic device,e.g., a balloon.

Typically, each of the cross-bar elements is shaped so as to define alumen therethrough, and comprises an elastic coupling band that passesthrough the lumen. Two portions of each of the coupling bands protrudefrom the cross-bar element, and are coupled to the base portion of theanchor at two respective points that are approximately opposite oneanother. In order to enable transesophageal insertion of the anchorusing a gastroscope, the anchor is typically stretched until it assumesan elongated position, in which the tube thereof is generally straight.The elastic coupling bands of the cross-bar elements enable the anchorto assume this elongated position, in which the cross-bar elements aredisplaced from their relaxed positions until they are approximatelyparallel with the tube of the anchor. A generally stiff rod is insertedinto a lumen of the tube, in order to maintain the stretched positionduring insertion. Once the anchor has been appropriately positioned inthe stomach, the rod is removed, allowing the anchor to assume itsrelaxed position.

As will be appreciated by those persons skilled in the art, a featureprovided by some embodiments of the present invention is the ease inwhich an anchor may be inserted into the gastrointestinal system.Another feature provided by some embodiments of the present invention isthe safety and security provided by the use of such an anchor. It istherefore an object of some embodiments of the present invention toprovide a safe and easy method of inserting and securing a floatinganchor into the gastrointestinal system so that a variety of devices maybe safely secured therein. It is another object of some embodiments ofthe present invention to safely and securely anchor a balloon in thestomach for promoting a feeling of satiety in a subject. Additionalobjects of embodiments of the present invention will become apparentfrom the following description.

There is therefore provided, in accordance with an embodiment of thepresent invention, apparatus for use in a gastrointestinal tract of asubject, the apparatus including:

a straightening rod;

a flexible tubular anchor having a distal end and an open proximal end,and sized to fit in the gastrointestinal tract, the anchor including amaterial that has an elastic memory which biases the anchor towardsassuming a pre-selected bent configuration, the anchor shaped so as todefine a central core extending from the open proximal end toward thedistal end, and the anchor configured to be straightened from thepre-selected bent configuration by insertion of the straightening rod inthe central core; and

a device coupled to the anchor, selected from the list consisting of: atherapeutic device, and a transmitting device.

For some applications, the distal end of the anchor is tapered. For someapplications, the bent configuration is selected from the groupconsisting of: a C-shaped configuration, an S-shaped configuration, aU-shaped configuration, a helical configuration, and a sinusoidalconfiguration, and the material has the elastic memory which biases theanchor towards assuming the selected bent configuration.

For some applications, the apparatus includes a pushing catheter shapedso as to define a bore therethrough, the catheter adapted to be axiallyaligned with the anchor, and the straightening rod is configured to beinserted through the catheter into the central core of the anchor.

In an embodiment, the anchor is shaped so as to define a wall having aguide wire canal therein.

In an embodiment, the device includes a transmitting device.

In an embodiment, the anchor is adapted to interfere with gastricemptying of the subject.

In an embodiment, the device includes the therapeutic device. For someapplications, the therapeutic device includes string-like attachments.For some applications, the therapeutic device includes a medicationadministration device. For some applications, the therapeutic device isadapted to administer tumor-targeting therapy.

In an embodiment, the therapeutic device includes an attachment adaptedto interfere with gastric emptying of a stomach of the subject when theanchor is placed in the stomach.

In an embodiment, the therapeutic device includes a balloon coupled to aballoon-coupling portion of the anchor. For some applications, theanchor includes a conduit wrapped around an external surface of theanchor, the conduit extending from the proximal end of the anchor to aninterior of the balloon.

In an embodiment, the balloon is adapted to promote a feeling of satietyin the subject. Alternatively or additionally, the balloon is adapted tointerfere with peristaltic waves and gastric emptying of the subject.

For some applications, the balloon includes a first balloon, and thetherapeutic device includes a second balloon.

In an embodiment, the balloon is positioned around the balloon-couplingportion of the anchor. For some applications, the anchor includesproximal and distal portions on respective sides of the balloon-couplingportion, and the balloon is coupled to the balloon-coupling portion andis not coupled to the proximal or distal portions. For someapplications, a length of the balloon-coupling portion of the anchor isless than 75% of a total length of the anchor, such as less than 50% ofthe total length of the anchor.

In an embodiment, the anchor is shaped so as to define a conduit channelextending from the proximal end of the anchor to an interior of theballoon. For some applications, the apparatus includes a conduit havingdistal and proximal ends, which is adapted to be placed through theconduit channel, such that the distal end opens to the interior of theballoon, and the proximal end opens outside of the anchor.

In an embodiment, a distal portion of the anchor has a curved shape whenthe anchor assumes the bent configuration. For some applications, thedistal portion of the anchor has a helical shape when the anchor assumesthe bent configuration. For some applications, a proximal portion of theanchor has a helical shape when the anchor assumes the bentconfiguration.

In an embodiment, a proximal portion of the anchor has a curved shapewhen the anchor assumes the bent configuration. For some applications,the proximal portion of the anchor has a helical shape when the anchorassumes the bent configuration.

In an embodiment, the anchor includes an elongated appendage extendingfrom the distal end thereof, the appendage having a distal end, theappendage configured to assume a position in which the distal endthereof is in a vicinity of the proximal end of the anchor when theanchor assumes the bent configuration. For some applications, theappendage includes a housing and a wire therein, and the wire includes afirst flexible segment, a second relatively stiff segment, and a thirdrelatively flexible segment. For some applications, the device includesa balloon coupled to the anchor, and the appendage is adapted to bedisplaced by the balloon when the balloon is inflated, such that thedistal end of the appendage is not in the vicinity of the proximal endof the anchor.

There is further provided, in accordance with an embodiment of thepresent invention, apparatus for use in a gastrointestinal tract of asubject, the apparatus including:

a straightening rod;

a flexible tubular anchor having a closed distal end and an openproximal end, the anchor including a material that has an elastic memorywhich biases the anchor towards assuming a pre-selected bentconfiguration, the anchor shaped so as to define a central coreextending from the open proximal end toward the distal end, and theanchor configured to be straightened from the pre-selected bentconfiguration by insertion of the straightening rod in the central core.

There is yet further provided, in accordance with an embodiment of thepresent invention, apparatus for use in a stomach of a subject, theapparatus including:

an elongated biocompatible anchor having proximal and distal portionsand a balloon-coupling portion therebetween, the anchor being sized tofit in the stomach; and

a balloon coupled to the balloon-coupling portion of the anchor, and notto the proximal or distal portions.

In an embodiment, the balloon is adapted to promote a feeling of satietyin the subject. Alternatively or additionally, the balloon is adapted tointerfere with peristaltic waves and gastric emptying of the subject.

In an embodiment, the anchor is adapted to interfere with gastricemptying of the subject.

In an embodiment, the anchor is adapted to assume a pre-selected bentconfiguration when in the stomach.

In an embodiment, the balloon is positioned around the balloon-couplingportion of the anchor. For some applications, a length of theballoon-coupling portion of the anchor is less than 75% of a totallength of the anchor, such as less than 50% of the total length of theanchor.

There is still further provided, in accordance with an embodiment of thepresent invention, a method including:

straightening a flexible tubular anchor that includes a material thathas an elastic memory which biases the anchor towards assuming apre-selected bent configuration, by inserting a straightening rod into acentral core extending from an open proximal end toward a distal end ofthe anchor;

inserting the straightened anchor with the rod therein into agastrointestinal tract of a subject; and

removing the anchor from the rod, thereby allowing the anchor to assumethe pre-selected bent configuration.

For some applications, inserting the straightened anchor includesthreading the anchor onto a guidewire. Alternatively, inserting thestraightened anchor includes inserting the anchor into an overtube.

For some applications, inserting the rod into the central core includesinserting the rod through a bore of a pushing catheter axially alignedwith the anchor, and then into the central core, and removing the rodfrom the anchor includes pushing the anchor off the rod by pushing onthe pushing catheter.

For some applications, inflating the balloon includes inserting aninflation conduit into the gastrointestinal tract, and inflating theballoon via the inflation conduit. For some applications, inflating theballoon includes inflating the balloon via an inflation conduit thatpasses through the conduit channel.

There is additionally provided, in accordance with an embodiment of thepresent invention, method including:

inserting, into a stomach of a subject, an elongated anchor havingproximal and distal portions and a balloon-coupling portiontherebetween;

inflating a balloon coupled to the balloon-coupling portion of theanchor, and not to the proximal or distal portions.

There is also provided, in accordance with an embodiment of theinvention, apparatus for use in a stomach of a subject, the apparatusincluding:

a balloon, adapted for placement in the stomach;

an anchor, coupled to the balloon and adapted to prevent the balloonfrom passing into a duodenum of the subject; and

an inflation tube, coupled to the balloon to permit inflation of theballoon, and adapted to stretch from the stomach to a mouth of thesubject to facilitate inflation of the balloon.

In an embodiment, the inflation tube is adapted to stretch to more than2.5 times a resting length thereof, e.g., from 2.5 to 10 times theresting length (such as six times the resting length).

In an embodiment, the anchor includes a resilient tube, and theapparatus includes a bend-limiting tube coupled to the resilient tube,which limits an extent of bending of the resilient tube.

In an embodiment, the inflation tube is configured to be disposed withinthe resilient tube, the resilient tube permitting the inflation tube toassume a straight position, or to bend up to a predefined limit.

In an embodiment, the anchor includes a material that has an elasticmemory which biases the anchor towards assuming a pre-selected bentconfiguration.

In an embodiment, the apparatus includes a straightening rod, and:

the anchor has a distal end and an open proximal end;

the anchor is shaped so as to define a central core extending from theopen proximal end toward the distal end; and

the anchor is configured to be straightened from the pre-selected bentconfiguration by insertion of the straightening rod in the central core.

In an embodiment, the balloon is adapted to promote a feeling of satietyin the subject.

In an embodiment, the balloon is adapted to interfere with peristalticwaves and gastric emptying of the subject.

In an embodiment, the apparatus includes a device coupled to the anchor,selected from the list consisting of: a therapeutic device, and atransmitting device.

In an embodiment, the apparatus includes a closure mechanism coupled toa proximal end of the inflation tube, configured₁₀ maintain pressurewithin the balloon by preventing leakage of fluid therefrom into thestomach of the subject.

In an embodiment, the apparatus includes an extraction tool configuredto stretch the inflation tube by reversibly engaging and pulling on theinflation tube.

In an embodiment, the apparatus includes a filling tube configured to betemporarily coupled to the inflation tube while the inflation tube isstretched, and configured to facilitate inflation of the balloon whenthe inflation tube is relaxed at least in part following beingstretched.

There is additionally provided, in accordance with an embodiment of theinvention, a method, including:

inserting into a stomach of a subject a gastric balloon in fluidcommunication with an inflation tube;

assessing an inflation level of the balloon following insertion thereof;

in response to identifying a need for inflation of the balloon,stretching the inflation tube while keeping the balloon within thestomach; and

inflating the balloon following the stretching of the inflation tube.

In an embodiment, assessing the inflation level of the balloon includesdetermining a level of weight loss of the subject and correlating weightloss to the level of inflation of the balloon.

In an embodiment, inflating the balloon includes injecting a fluid intothe inflation tube while a proximal end of the inflation tube is outsideof a body of the subject.

In an embodiment, the method includes temporarily coupling the inflationtube to a filling tube following the stretching of the inflation tube,and wherein inflating the balloon includes:

allowing at least a portion of the inflation tube to return to thestomach while the filling tube is coupled to the inflation tube; and

injecting a fluid into the inflation tube via the filling tube while theportion of the inflation tube remains disposed within the stomach.

In an embodiment, stretching the inflation tube includes extracting aproximal portion of the inflation tube from a mouth of the subject.

In an embodiment, extracting the proximal portion of the inflation tubeincludes stretching the inflation tube to at least 2.5 times a restinglength thereof.

There is further provided, in accordance with an embodiment of thepresent invention, apparatus for use in a stomach of a subject, theapparatus including an anchor, which includes:

a flexible tube, which, when in a relaxed position, is shaped so as todefine a generally planar base portion that prevents the anchor frompassing into a duodenum of the subject; and

at least two cross-bar elements having ends which are positioned in avicinity of the base portion, which cross-bar elements are configured tohelp maintain a shape of the base portion.

In an embodiment, the anchor is configured to be positioned in an antrumof the stomach such that the anchor to some extent interferes withnatural antral contractions of the antrum.

For some applications, the tube is shaped so as to define a proximalportion that projects away from a plane defined by the base portion, andthe apparatus includes a balloon coupled to the proximal portion of thetube. For some applications, the anchor includes at least one sleevethat encloses one of the cross-bar elements.

In an embodiment, the cross-bar elements are shaped so as to definerespective lumens therethrough, and the cross-bar elements includerespective elastic coupling bands that pass through the respectivelumens. For some applications, two portions of each of the couplingbands protrude from the respective cross-bar element, and are coupled tothe base portion at two respective points that are approximatelyopposite one another on the base portion. For some applications, theanchor is configured, when stretched, to assume an elongated position inwhich the tube is generally straight, and in which the cross-barelements are positioned approximately parallel with the tube.

The method and apparatus of the present invention will be betterunderstood by reference to the following detailed discussion of specificembodiments and the attached figures, which illustrate and exemplifysuch embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a floating gastrointestinal anchor, inaccordance with an embodiment of the present invention;

FIGS. 2 and 3 are a side view and a cross-sectional view, respectively,of another configuration of the anchor of FIG. 1, in accordance with anembodiment of the present invention;

FIG. 4 is a side view of the embodiment depicted in FIG. 2, showing aninflated balloon, in accordance with an embodiment of the presentinvention;

FIG. 5 is a side view of another floating gastrointestinal anchor, inaccordance with an embodiment of the present invention;

FIG. 6 is a side view of the anchor of FIG. 5, showing balloons in aninflated state, in accordance with an embodiment of the presentinvention;

FIG. 7 is a side view of an embodiment of the anchor of FIG. 1 in astraightened position prior to insertion into the gastrointestinaltract, in accordance with an embodiment of the present invention;

FIG. 8 is an illustration of an appendage attached to the distal end ofthe anchor of FIG. 1, in accordance with an embodiment of the presentinvention;

FIGS. 9 and 10 illustrate an attachment coupled to the anchor of FIG. 1,in accordance with respective embodiments of the present invention;

FIG. 11 is a side view of a device and a balloon attached to the anchorof FIG. 1, in accordance with an embodiment of the present invention;

FIG. 12A is a side view of a configuration of the anchor of FIG. 1 inwhich the anchor has a helically-shaped distal end and a conduit canalwithin a central core thereof, in accordance with an embodiment of thepresent invention;

FIG. 12B is an enlarged view of the proximal end of the configurationshown in FIG. 12A, in accordance with an embodiment of the presentinvention;

FIGS. 13-16 are schematic illustrations of obesity treatment apparatusduring different phases thereof, in accordance with an embodiment of thepresent invention;

FIGS. 17A and 17B are schematic illustrations of a bend-limiting tubefor insertion into a gastrointestinal anchor, in accordance with anembodiment of the present invention;

FIG. 18 is a schematic illustration of another floating gastrointestinalanchor, in accordance with an embodiment of the present invention;

FIG. 19 is a schematic illustration of the anchor of FIG. 18 in astretched position, in accordance with an embodiment of the presentinvention; and

FIGS. 20A-D are schematic illustrations of the deployment of the anchorof FIG. 18, in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

The following preferred embodiments as exemplified by the drawings areillustrative of embodiments of the invention, and are not intended tolimit the invention as encompassed by the claims of this invention.

A floating gastrointestinal anchor 1, as generally illustrated in thefigures, is provided for securing devices in the gastrointestinal tract.The gastrointestinal tract, as used herein, includes the esophagus.Although devices and methods are described in some embodiments as beinguseful for anchoring an inflated balloon in the stomach for affectingweight loss, it is to be understood that the methods and devicesdescribed herein can be used for securing any device for its intendedpurpose anywhere in the gastrointestinal tract.

FIG. 1 depicts floating gastrointestinal anchor 1, in accordance with anembodiment of the present invention. As shown in the embodiment of FIG.1, anchor 1 has a generally “C” or “U” shape. The anchor has a distalend 2, a proximal end 4, and a side wall 5. The distal end ispreferentially tapered for ease of insertion. Proximal end 4 is shapedso as to define an aperture 6 opening into a central core 7, whichextends through substantially the entire length of the anchor. Thedistal end may be either open or closed. The distal end is typicallytapered. A rigid insertion rod 8 (described hereinbelow with referenceto FIG. 7) is inserted into aperture 6 and central core 7 duringinsertion of the anchor into the subject. Anchor 1 is made of a materialthat is flexible enough to be straightened, but has an elastic “memory”to conform to a pre-selected bent shape. The elastic memory may beimparted by the material itself, or alternatively, by the addition ofanother material. For example, the shape to which the anchor reverts maybe determined by the inclusion of an additional material having a memorysuch as spring steel or a plastic insert. The anchor material comprisesa biocompatible material that can withstand the acid environment of thestomach, as is well known to those skilled in the art.

For some applications, located approximately midway between the distalend and the proximal end of the anchor is a balloon 10, which is fixedto and typically surrounds the anchor. Balloon 10 is shown in FIG. 1 inits deflated state. The balloon is typically manufactured ofbiocompatible material that can withstand the acid environment of thegastric lumen. A conduit channel 11 is typically formed in side wall 5of the anchor. This conduit channel allows for a thin-walled conduit(not shown) to pass along the side wall of the anchor and into theinterior space of balloon 10 for eventual inflation thereof. A guidewirecanal 12 is typically formed in the wall of anchor 1 for inserting aguidewire during insertion of the anchor into the stomach.Alternatively, an overtube may be used in lieu of a guidewire duringinsertion of the anchor into the gastrointestinal tract. If the diameterof the anchor is sufficiently small, a biopsy channel of an endoscopemay be used as an overtube to direct the anchor into thegastrointestinal tract.

It is to be noted that balloon 10 may be located with respect to theanchor at the proximal or distal ends or at any site therebetween.

FIGS. 2 and 3 are a side view and a cross-sectional view, respectively,of another configuration of anchor 1 of FIG. 1, in accordance with anembodiment of the present invention. In this configuration, conduitchannel 11 of FIG. 1 has been replaced with a conduit canal 14 formedwithin side wall 5 of anchor 1. For some applications, side wall 5 ofthe anchor is shaped so as define guidewire canal 12, to allow passageof a guidewire, such as a standard guidewire, e.g., a standard 0.028inch guidewire, as is well known in the art (as shown in FIG. 3).

FIG. 4 shows anchor 1 of FIG. 2 with a thin-walled conduit 16 insertedinto conduit canal 14 of side wall 5 of the anchor and threaded into theinterior of balloon 10. (Alternatively, conduit 16 is inserted intoconduit channel 11 of side wall 5, as described hereinabove withreference to FIG. 1.) Balloon 10 is shown in its inflated state in FIG.4. A proximal end 18 of conduit 16 extends a sufficient distance, forexample 60 cm, to allow passage of the conduit out of the mouth of thesubject while the anchor with the inflated balloon is in the gastriclumen. A fitting 20 is at proximal end 18 of the conduit 16. Fitting 20typically comprises a “luer-lock” type or equivalent self-sealingmechanism, as is well known to those skilled in the art, for allowinginflation of a balloon in a sealed system. The insertion of the ballooninto the stomach promotes a feeling of satiety in the subject andgenerally interferes with peristaltic waves and gastric emptying. Forsome applications, conduit 16 is wrapped around an external surface ofanchor 1, rather than passed through conduit canal 14 of FIG. 2 orconduit channel 11 of FIG. 1. For these applications, anchor 1 typicallyis shaped so as to define neither conduit canal 14 nor channel 11.

The caliber of the conduit and its lumen are typically sufficient toallow inflation of any balloon. The conduit comprises a biocompatiblematerial that can withstand the acid environment, and can flex with theanchor in its different conformations. The balloon(s) are inflated to avolume sufficient to fill or partially fill the gastric lumen, which istypically between about 400 and about 1000 cc, depending on stomachsize. The anchor typically has external markings from the end of thetapered tip, e.g., every 5 cm, to help guide the operator.

FIG. 5 shows an anchor 22, in accordance with an embodiment of thepresent invention. Except as described below, anchor 22 is generallysimilar to anchor 1, described hereinabove with reference to FIGS. 1-4.Anchor 22 is shaped so as to have an “S” configuration, and comprisestwo or more balloons, e.g., a distal balloon 24 and a proximal balloon26. For some applications, anchor 22 is shaped so as not to include theportion of the anchor proximal to the proximal balloon. In themulti-balloon configuration shown in FIG. 5, a corresponding number ofrespective canals are used for guiding conduits into the respectiveinteriors of the balloons. A distal canal 28 guides distal conduit 30 todistal balloon 24, and a proximal canal 32 guides proximal conduit 34 toproximal balloon 26. If more than two balloons are provided, acorresponding number of conduits are used in the same manner. Theinflation ports are marked proximal and distal in such a way that iseasily recognizable to an endoscopist upon viewing in the gastric lumen.

FIG. 6 shows anchor 22 of FIG. 5 with the proximal and distal balloonsin their inflated state.

FIG. 7 is a side view of anchor 1 in a straightened position prior toinsertion into the gastrointestinal tract, in accordance with anembodiment of the present invention. Rigid rod 8 is typically extendedthrough the entire length of central core 7 of anchor 1, causing anchor1 to assume a generally straight configuration. (Alternatively, therigid rod is extended through only a portion of the length of thecentral core.) A pushing catheter 36 having a proximal end 37 and adistal end 38 is shown in axial alignment with anchor 1. The pushingcatheter 36 has a bore 39 extending entirely therethrough. Rod 8 extendsentirely through bore 39 and outside of proximal end 37 of the pushingcatheter. Rigid rod 8 typically comprises a rigid unbendablebiocompatible material, which easily slips in and out of the pushingcatheter. Alternatively, the rigid rod comprises a generally rigidbiocompatible material, which, although slightly bendable, issufficiently rigid to as to easily slip in and out of the pushingcatheter. Rigid rod 8 is sufficiently long to fully engage bore 39 ofpushing catheter 36, and to extend out of distal end 38 of pushingcatheter 36 by between about 35 and about 55 cm, e.g., by approximately40 cm or approximately 45 cm, for the C-shaped configuration describedhereinabove with reference to FIGS. 1-4. The distal portion of rod 8which extends past distal end 38 of pushing catheter 36 is inserted intocentral core 7 of anchor 1. When used with other configurations, such asthe S-shaped configuration described hereinabove with reference to FIGS.5 and 6, or the helical configuration described hereinbelow withreference to FIGS. 12A-B, rod 8 has a length appropriate for the lengthof the core of these configurations.

A pushing tab 40 is preferentially provided in a vicinity of proximalend 37 of the pushing catheter. Tab 40 is used by the endoscopist topush anchor 1 off rod 8, by pushing the tab forward while holding theproximal end of rod 8 stationary with respect to the mouth of thesubject. The pushing catheter typically comprises a biocompatible rigidunbendable material, or a generally rigid, but slightly bendablematerial.

After anchor 1 has been inserted into the gastrointestinal tract and thestraightening rod has been removed, the anchor assumes its “C”, “S”,“U”, or any other pre-selected bent shape that the anchor has beenconfigured to assume. By assuming a pre-selected bent shape, the anchorgenerally prevents migration of the inserted device. The anchor materialis flexible enough to enable straightening for deployment, and has amemory shape that remains after rod 8 has been removed. In this way, itfacilitates safe atraumatic endoscopic removal, even after havingassumed its memory shape. As appropriate, anchor 1 may be partially orcompletely straightened during removal. Anchor 1 allows carriage of oneor more balloons, transmitters, cameras, or any other device that isdesired to be placed in the gastric lumen.

Anchor 1, when in the C-configuration described hereinabove withreference to FIGS. 1-4, typically has a total length of between about 30and about 55 cm, e.g., approximately 40 cm. A central, generallystraight, portion typically has a length of between about 15 and about25 cm, e.g., approximately 16 cm or approximately 20 cm, and each endportion typically has a length of between about 8 and about 15 cm, e.g.,approximately 10 cm or approximately 12 cm. These dimensions may, ofcourse, vary depending on stomach shape and size. Other areas of thegastrointestinal tract require various shapes and sizes. Typically,distal end 2 of anchor 1 is closed and is tapered with a soft flexibletip to allow easy passage through the gastrointestinal tract.

FIG. 8 illustrates an appendage 42 attached to distal end 2 of anchor 1,in accordance with an embodiment of the present invention. Appendage 42may also be attached to distal end 2 of anchor 22, described hereinabovewith reference to FIGS. 5-6 (configuration now shown). Appendage 42comprises a wire 45 that is housed in a flexible shaft 44. The appendageis preferably an elongated continuation of distal tip 2, comprising thesame material as distal tip 2. The appendage is preferably string-likeand approximately 3-5 mm in diameter. Wire 45 housed therein istypically a unitary piece, which typically comprises a first relativelyshort relatively flexible segment 46 (e.g., having a length ofapproximately 5 cm). As the wire continues within this “string”appendage, a longer relatively stiff segment 48 (e.g., having a lengthof approximately 8-10 cm) is followed by a third flexible segment 50(e.g., having a length of approximately 3 cm). Wire 45 alternativelycomprises a different arrangement of alternating flexible and stiffsegments, each having various lengths.

When balloon 10 is in its deflated state, appendage 42 typically assumesthe position shown in FIG. 8, such that a distal end 52 of appendage 42is positioned in a vicinity of proximal end 4 of anchor 1 (for clarityof illustration, balloon 10 is not shown in FIG. 8; the balloon can beseen in its deflated state in FIG. 1, for example). In this position,appendage 42 provides additional safety for the device when balloon 10is not inflated. Appendage 42 closes off the gap between proximal end 4and distal end 2 of anchor 1, thereby preventing any undesired migrationout of the stomach and into the pylorus. When balloon 10 is inflated, asshown, for example, in FIG. 4, appendage 42 is easily displaced by theballoon (such that distal end 52 of appendage 42 is no longer positionedin the vicinity of proximal end 4 of anchor 1).

FIGS. 9 and 10 illustrate an attachment 60 coupled to anchor 1, inaccordance with respective embodiments of the present invention.Attachment 60 may also be attached to anchor 22, described hereinabovewith reference to FIGS. 5-6 (configuration not shown). Attachment 60comprises one or more elements 48, which may comprise, for example,cord, ribbon, sponges, other thin material, or a combination thereof.Elements 48 typically comprise a biocompatible material. Attachment 60is adapted to occupy all or a portion of the antrum, thereby interferingwith gastric emptying. For some applications, as shown in FIG. 9,attachment 60 is used in lieu of balloon 10. In these applications,attachment 60 may be coupled to a central portion of anchor 1, forexample. Alternatively, for some applications, as shown in FIG. 10,attachment 60 is used in combination with balloon 10. In theseapplications, attachment 60 may be coupled to a lateral arm of anchor 1,for example.

FIG. 11 illustrates a device 70 connected to anchor 1, in accordancewith an embodiment of the present invention. Device 70 comprises atransmitting device or any other device, such as a camera which could beplaced separately, or in combination with any other device, such asballoon 10 (as shown in FIG. 11). Device 70 may also comprise anothertype of therapeutic device; for example, device 50 may comprise a devicefor administering medication or a device for targeting a tumor. For someapplications in which device 70 comprises a device for targeting atumor, device 70 is adapted to administer chemotherapy, radiationtherapy, photodynamic therapy, tumor ablation therapy, seed implanttherapy, or any other anti-tumor therapy known to those skilled in theart.

Reference is made to FIGS. 12A and 12B, which illustrate a configurationof anchor 1 in which the anchor assumes the bent shape of a helix at itsdistal end, in accordance with an embodiment of the present invention.For some applications, conduit canal 14 is placed within central core 7.Balloon 10 may be inflated in the conventional manner. The diameter ofthe helix is typically such that it is not able to pass through thepylorus, for example, between about 4 cm and about 20 cm, e.g., betweenabout 8 cm and about 14 cm. A device is coupled to the straight lengthof the anchor, such as a therapeutic device, e.g., balloon 10; atransmitting device, e.g., a camera or other transmitting device; orother therapeutic device 70. For some applications, a proximal end ofthe anchor has a curved tip (e.g., assumes the bent shape of a helix),which generally diminishes tissue trauma by creating an atraumaticsurface.

Distal end 2 of the anchors described hereinabove with reference toFIGS. 1-12B is typically not tapered, but rather is rounded to preventtissue damage upon contact. The anchor typically has an approximately7-35 Fr caliber, e.g., an approximately 7-20 Fr or an approximately25-35 Fr caliber. For some applications, an interior surface of theanchor comprises a biocompatible material different from that of theremainder of the anchor, in order to allow passage of rod 8 and/or forshape maintenance. For applications in which separate guidewire canal 12is not provided, the anchor typically has a smaller caliber, e.g.,approximately 6 to 16 Fr. Further alternatively, central core 7 of theanchor is used for a guidewire or for a combinationguidewire/straightening rod.

Deployment

It is to be understood that the following examples of use of embodimentsof the present invention are not intended to restrict the scope of thepresent invention.

In an embodiment of the present invention, deployment of thegastrointestinal devices described herein is performed using a gastricovertube or over a guidewire. These standard, well-establishedtechniques are adapted for use with the novel techniques and devicesdescribed herein. The guidewire method has been described in the uppergastrointestinal tract with reference to esophageal strictures. Forexample, techniques may be used that are described in theabove-mentioned articles by Kadakia S C et al., Fleischer D E et al.,and/or Dumon J R et al., mutatis mutandis, including techniques foresophageal dilators passed over guidewires without the need forfluoroscopy.

In an embodiment of the present invention, the anchors described hereinare deployed using the Savary system guidewire technique described byDumor J R et al., modified as described immediately hereinbelow. Upperendoscopy is performed with complete evaluation of the esophagus stomachand duodenum. The endoscopist measures the distance from the incisors tothe gastro-esophageal junction. With the endoscope in the gastricantrum, the guidewire (flexible tip first) is passed under direct visioninto the gastric antrum. The guidewire is advanced as the endoscope isremoved leaving the guidewire in the gastric lumen. The free end of theguidewire (outside of the mouth) is then placed into the guidewire lumenof the anchor. The anchor is slid down over the guidewire (withoutchanging the position of the guidewire relative to the mouth) and passedinto the mouth down the esophagus. When the external markings on theanchor at the incisors are 6-8 cm greater than the level of thegastro-esophageal junction (as noted by the endoscopist during theinitial endoscopy), the pushing tab of the pushing catheter is pushedforward while holding the rod stationary relative to the mouth of thesubject. Once the anchor is free of the rod, the rod, guidewire, andpushing catheter are removed. The conduit(s) inflation port(s) remainoutside of the mouth. The endoscope is then re-inserted to inspect theposition of the anchor, and any necessary adjustments are made. Theconduit inflation port is then accessed with a luer-lock syringe andinflated with approximately 400-1000 cc of fluid, depending on stomachsize, which can be viewed endoscopically. This is repeated forembodiments of the anchor that comprise multiple balloons. The conduittubing is then pulled down into the stomach using a snare, hookcatheter, grabbing forceps, or equivalent. Once the conduit tubing is inthe gastric lumen, the endoscope is then removed and the procedure iscomplete.

If at a later time the balloon(s) need to be adjusted, endoscopy withsnare, hook catheter, grabbing forceps, or equivalent access of the freeend of the conduit tubing can be performed. The conduit is pulled out ofthe mouth and inflation or deflation performed, followed by pulling thefree end of the conduit into the gastric lumen as described above. Aswill be evident to those skilled in the art who have read the presentapplication, the embodiments described herein may be placed into thegastrointestinal tract using numerous methods for insertion.

In an embodiment of the present invention, the anchors described hereinare deployed using a standard gastric overtube method, modified asdescribed immediately hereinbelow. Standard endoscopy is performed withinspection of the esophagus stomach and duodenum. The endoscope is thenremoved and a gastric overtube is placed, typically using ordinarytechniques. Techniques are typically used that are described in theabove-mentioned article by Werth et al., for use of a gastric overtubefor foreign body removal and for multiple endoscopic intubations. Oncethe overtube is in place, the anchor is placed through the overtube. Asdescribed hereinabove regarding the guidewire technique, the pushingcatheter tab is pushed once the distal tip of the anchor is 6-8 cmbeyond the gastro-esophageal junction. When the anchor is off the rod,the rod and pushing catheter are removed. The endoscope can then passthrough the overtube and inspect the anchor position, as describedhereinabove. The remainder of the procedure is the same as the guidewireprocedure described hereinabove.

The anchor, having reverted to its pre-selected bent shape, prevents adeflated balloon from migrating, thereby providing a safe weight lossdevice. The anchor can be used to anchor more than one balloon, and cananchor any device that needs to remain in the gastric lumen. The anchorcan be used in a post-bariatric surgical subject whose weight loss hasplateaued and who wishes further weight loss. It can be used anywhere inthe gastrointestinal tract where a device of any kind needs to remain inplace. The site of the anchor will determine its pre-determined shape,geometry, and size. It is typically placed endoscopically and removedendoscopically under conscious sedation in an outpatient setting.

Reference is now made to FIGS. 13-16, which are schematic illustrationsof obesity treatment apparatus 90 comprising a balloon 92 and a floatinggastrointestinal anchor 102 coupled thereto, in accordance with anembodiment of the present invention. In general, techniques describedhereinabove with respect to other anchors and balloons may be used withapparatus 90, mutatis mutandis.

As is shown in FIG. 13, a highly-stretchable inflation tube 96 protrudesfrom a first end of balloon 92, typically by a length L2 of about 1-6 cm(e.g., about 2-4 cm). A length L1 of tube 96 of about 6-12 cm (e.g.,about 8-9 cm) remains within balloon 92. Tube 96 typically comprisessilicone or other stretchable elastomer, or another biocompatiblematerial capable of stretching to at least about 2.5-10 times itsoriginal length (e.g., 6 times its original length). Inflation tube 96is shown in FIG. 13 in an unstretched state, in which an outer diameterD1 thereof is typically about 2-4 mm, e.g., 3 mm. Inflation tube 96 isdisposed within a supporting tube 94, which is typically bendable andresilient, and comprises silicone or another suitable material. Supporttube 94 is typically fixed to balloon 92 at either end using a sealant104, which typically comprises a silicone-based or other biocompatibleadhesive. An inflation hole 98 in support tube 94, and optionally ininflation tube 96, provides fluid communication between the lumen ofballoon 92 and the lumen of tube 96. A closure mechanism 120 typicallycomprising a luer lock and/or a hand-tightened cap maintains pressurewithin balloon 92 by preventing fluid leakage therefrom into thesubject's stomach.

A rod insertion tube 100 allows insertion of a rigid rod (like rod 8described hereinabove with reference to FIG. 7) to straighten anchor 102at the time of implantation of apparatus 90. Once apparatus 90 islocated within the subject's stomach, the rigid rod is removed, andanchor 102 assumes an anchoring shape (e.g., the helical shape shown inFIG. 13). Anchor 102 typically but not necessarily remains in theantrum, adjacent to the pyloric valve, and to some extent slows passageof chyme into the duodenum and thereby enhances the sensation ofsatiety.

FIG. 13 schematically shows balloon 92 in a partially inflated state, asit may be in the stomach during an initial trial period designed toascertain whether that level of inflation is sufficient to treat thesubject's obesity. If it is determined that the inflation of the balloonis not sufficient, e.g., if the subject is not losing sufficient weight,then balloon 92 is further inflated, as shown in FIGS. 14-16. Similarly,if over the long term the level of inflation of the balloon decreases,then the balloon may be further inflated as shown in FIGS. 14-16.

As shown in FIG. 14, an endoscopic extraction tool 110 couples withclosure mechanism 120 or with inflation tube 96, using techniques knownin the art, and stretches inflation tube 96 such that it withdrawsclosure mechanism 120 out of the stomach, through the subject'sesophagus, and into (or out of) the subject's mouth. Due to thisstretching, the outer diameter of inflation tube 96 decreases to a newdiameter D2, smaller than D1. If inflation tube 96 in this stretchedstate is able to facilitate re-inflation of balloon 92, then closuremechanism 120 is opened while in or just outside of the subject's mouth,and balloon 92 is inflated via inflation tube 96.

Reference is now made to FIG. 15. If it is not practical to inflateballoon 92 while inflation tube 96 is thus stretched, then a temporaryfilling tube 132 is coupled to closure mechanism 120 or to a temporarycoupling valve 130, in order to provide fluid communication betweentubes 96 and 132. Inflation tube 96 is gradually returned to thestomach, substantially returning its diameter to D2, and the balloon isinflated by fluid passing through temporary filling tube 132 andinflation tube 96. Subsequently, temporary filling tube 132 is decoupledfrom inflation tube 96, and closure mechanism 120 is closed, in order tomaintain the balloon in its newly inflated state, as shown in FIG. 16.

As appropriate, a similar technique may be used to partially orcompletely deflate balloon 92.

Reference is now made to FIGS. 17A and 17B, which are schematicillustrations of a bend-limiting tube 140 for placement intogastrointestinal anchor 102 or another anchor, in accordance with anembodiment of the present invention. Bend-limiting tube 140 typicallybut not necessarily comprises stainless steel, and is shaped to define aplurality of slits 142 which permit tube 140 to assume a straightposition, or to bend up to a predefined limit. As appropriate for agiven application, the dimensions of slits 142 may differ from thoseshown in FIGS. 17A and 17B. For example, they could be configured toallow more or less bending of bend-limiting tube 140. Additionally,although slits 142 are shown to be on only one side of bend-limitingtube 140, for some applications the slits are placed in differentpositions from those shown, so as to, for example, permit limited backand forth flexing of tube 140, or bending in any direction. For example,for applications in which bend-limiting tube 140 is configured forinsertion into gastrointestinal anchor 102, slits 142 are placed on tube140 so as to allow anchor 102 to assume the position shown in FIG. 15,but to inhibit excess curvature of anchor 102 to develop.

For some applications, bend-limiting tube 140 is replaced orsupplemented by other bend-limiting tubes for inhibiting excess bending.For example, a series of chained or free beads may be disposed within abend-limiting tube running along the length of anchor 102, and the closeproximity of the beads to each other may be used to limit local bending.As appropriate, the beads may comprise spherical beads or shaped beadswith protrusions, so as to limit bending of the anchor. Alternatively oradditionally, a bend-limiting tube placed within anchor 102, or runningalong the length of anchor 102, comprises multiple closely-spaced ringssurrounding the bend-limiting tube, whereby excess bending of thebend-limiting tube and the anchor is prevented by contact of the rings.

Reference is made to FIG. 18, which is a schematic illustration of afloating gastrointestinal anchor 200, in accordance with an embodimentof the present invention. A proximal end 210 of anchor 200 is typically,but not necessarily, coupled to a device, such as a therapeutic device,e.g., a balloon; a transmitting device, e.g., a camera or othertransmitting device; or other therapeutic device. For example, proximalend 210 may be coupled to a balloon such as balloon 92, describedhereinabove with reference to FIGS. 13-16. Anchor 200 may alternativelyor additionally be used in combination with other techniques describedhereinabove. Anchor 200 typically, but not necessarily, is positioned inan antrum 212, adjacent to the pyloric valve, and to some extentinterferes with natural antral contractions, thereby slowing gastricemptying and enhancing the sensation of satiety.

Anchor 200 comprises a flexible tube 220, which, in its relaxedposition, is typically shaped so as to define a generally planar baseportion 222, and a proximal portion 224 that projects away from theplane defined by base portion 222, typically in an approximatelyperpendicular direction. Typically, base portion 222 is generallycircular. Alternatively, portion 22 has another shape, such as arectangle, e.g., a square, or an ellipse. It is noted that the shapedescribed herein and shown in FIG. 18 reflects anchor 200 when it is inits relaxed position. When deployed in the stomach, the shape of theanchor may change because of forces applied thereto by the stomach wall.For some applications, tube 220 comprises silicone, nylon, Pebax®(Arkema), Teflon® (DuPont), stainless steel, nitinol, titanium, oranother biocompatible material.

Anchor 200 further comprises at least two cross-bar elements 230, theends of which are positioned in a vicinity of base portion 222. Forapplications in which the anchor comprises exactly two cross-barelements, the two elements are typically approximately perpendicular toone another when the anchor is in its relaxed position, as shown in FIG.18. The cross-bar elements help maintain the shape of the anchor, sothat the anchor interferes with gastric emptying, as mentioned above,and so that the anchor does not pass into a duodenum of the subject. Forsome applications, cross-bar elements 230 comprise a rigid material,such as metal (e.g., stainless steel), or nylon, Pebax® (Arkema),Teflon® (DuPont), or another similar material, with or without metalinserts, while for other applications the elements comprise a moreflexible, but still generally rigid, material, such as plastic orsilicone.

Typically, each of cross-bar elements 230 is shaped so as to define alumen therethrough, and comprises an elastic coupling band 232 thatpasses through the lumen. Two portions of each of coupling bands 232protrude from the cross-bar element, and are coupled to base portion 222at two respective points that are approximately opposite one another.For some applications, bands 232 are generally rigid in central areasthereof, while elastic near the ends thereof. Alternatively, cross-barelements 230 do not comprise coupling bands 232, and are instead coupleddirectly to base portion 222. Further alternatively, exactly one end ofeach cross-bar element is coupled directly to base portion 222.

For some applications, respective central portions 240 of cross-barelements 230 are shaped so as to define respective cut-outs 242, whichbetter enable the cross-bar elements to occupy approximately the sameplane. Alternatively, the central portions are shaped to defineindentions that are not cut out. Further alternatively, the cross-barelements are slightly arced in opposite directions, so as to allow thecross-bar elements to intersect one another while remainingapproximately in a single plane. Still further alternatively, thecross-bar elements are shaped like simple cylinders.

For some applications, anchor 200 further comprises sleeves 244, each ofwhich encloses a respective cross-bar element 230 and all or a portionof the respective coupling band 232 that protrudes from the cross-barelement. The ends of the sleeves are typically coupled to base portion222 at the points at which the respective coupling bands are coupled(e.g., as shown in FIG. 19). In this configuration, each sleeve servesas a backup in the event that the respective coupling band 232 fails.Alternatively, sleeves 244 are coupled to the respective bands or tocross-bar elements 230. In either case, sleeves 244 typically helpprevent the contents of the stomach from entering cross-bar elements230. (For the sake of clarity, sleeves 244 are not shown in FIGS. 20A-D,although they may be provided.)

For applications in which base portion 222 is generally circular, thebase portion typically has a diameter of between about 5 and about 10cm, such as about 7 cm, and cross-bar elements 230 have correspondinglengths. Tube 220 of base portion 222 typically has a cross-sectionalouter diameter of between about 5 and about 10 mm, such as about 8 mm.The cross-bar elements typically have a cross-sectional outer diameterof between about 4 and about 10 mm, such as about 6 mm. Although manyportions of the implantable apparatus described herein have circularcross-sectional shapes, the scope of the present invention include theuse of other cross-sectional shapes, as well.

Reference is made to FIG. 19, which is a schematic illustration ofanchor 200 in a stretched position, in accordance with an embodiment ofthe present invention. In order to enable transesophageal insertion ofanchor 200 using a gastroscope, the anchor is typically stretched untilit assumes an elongated position, in which tube 220 is generallystraight. Elastic coupling bands 232 of cross-bar elements 230 enablethe anchor to assume this elongated position, in which the cross-barelements are displaced from their relaxed positions until they areapproximately parallel with tube 220. A generally stiff rod is insertedinto a lumen of tube 220, in order to maintain the stretched positionduring insertion (rod not shown in figures). Once the anchor has beenpartially or completely positioned in the stomach, the rod is removed,allowing the anchor to assume its relaxed position.

FIGS. 20A-D are schematic illustrations of the deployment of anchor 200,in accordance with an embodiment of the present invention. Prior toinsertion of anchor 200 into the subject, a guidewire 252 istransesophageally inserted into a stomach 250, such as using angastroscope, as is known in the art. The distal end of the guidewire ismaneuvered to antrum 212, and the gastroscope is removed from thesubject. (Insertion of guidewire 252 is not shown in the figures.)Anchor 200 is configured to assume its elongated position, by insertingthe generally stiff rod into the lumen of tube 220, as describedhereinabove with reference to FIG. 19. As shown in FIG. 20A, theelongated anchor is transesophageally inserted into stomach 250 overguidewire 252, which passes through a lumen of the elongating rod.

As shown in FIGS. 20B-C, once in stomach 250, anchor 200 is allowed togradually return to its relaxed position, by withdrawal of the rod.Withdrawal of the rod typically includes pushing a portion of theimplantable apparatus (e.g., balloon 260 or anchor 200) off of the rod.For some applications, a distal tip of a pushing tool (not shown) iscoupled to the portion of the implantable apparatus such that, ifdesired, the pushing tool can also at least partially pull the portionof the implantable apparatus back onto the rod. For these applications,the pushing tool typically grasps or is otherwise releasably coupled tothe portion of the implantable apparatus, and can be released by thephysician from the portion when the rod is sufficiently withdrawn.Anchor 200 is shown partially relaxed in FIG. 20B, and fully relaxed inFIG. 20C. It is noted that the withdrawal of the elongating rodtypically begins as soon as possible during the insertion procedure (andprior to the anchor reaching the antrum), in order to minimize thelikelihood of the rod applying undue forces to the stomach. In theembodiment shown in FIG. 20C, anchor 200 is coupled to a balloon 260,such as balloon 92, described hereinabove with reference to FIGS. 13-16.In FIG. 20D, balloon 260 has been fully inflated, anchor 200 ispositioned in antrum 212, and guidewire 252 is withdrawn from thesubject. Typically, a gastroscope is used for visually confirming properplacement and deployment of the anchor and/or inflation of balloon 260.

The scope of the present invention includes the use of any of theanchors described hereinabove without simultaneous use of a balloon. Inthese embodiments, the anchor typically slows gastric emptying and/orfills space and thereby induces a sensation of satiety. As appropriate,generally helical anchors described hereinabove and shown in the figuresmay include more turns, for example so as to occupy half of the stomachor even substantially all of the stomach (instead of just the portionnear the antrum, as shown in some of the figures).

Embodiments described herein may be practiced in combination withtechniques described in one or more of the following applications, whichare assigned to the assignee of the present patent application and areincorporated herein by reference: U.S. patent application Ser. No.11/132,855, filed May 18, 2005; US Provisional Patent Application60/639,843, filed Dec. 27, 2004; PCT Patent ApplicationPCT/IL2005/001381, filed Dec. 27, 2005; U.S. Provisional Patentapplication 60/787,124 filed by Brooks on Mar. 28, 2006, entitled,“Floating gastrointestinal anchor”; and U.S. Provisional Patentapplication 60/815,624 filed by Brooks on Jun. 20, 2006, entitled,“Floating gastrointestinal anchor.” The scope of the present inventionincludes embodiments described in each of these five applications.

It will be appreciated by persons skilled in the art that the presentinvention is not limited to what has been particularly shown anddescribed hereinabove. Rather, the scope of the present inventionincludes both combinations and subcombinations of the various featuresdescribed hereinabove, as well as variations and modifications thereofthat are not in the prior art, which would occur to persons skilled inthe art upon reading the foregoing description.

1. Apparatus for use in a stomach of a subject, the apparatuscomprising: a balloon, adapted for placement in the stomach; an anchor,coupled to the balloon and adapted to prevent the balloon from passinginto a duodenum of the subject; and an inflation tube, coupled to theballoon to permit inflation of the balloon, and adapted to stretch fromthe stomach to a mouth of the subject to facilitate inflation of theballoon.
 2. The apparatus according to claim 1, wherein the inflationtube is adapted to stretch to more than 2.5 times a resting lengththereof.
 3. The apparatus according to claim 1, wherein the anchor isconfigured to be positioned in an antrum of the stomach such that theanchor interferes at least to some extent with natural antralcontractions of the antrum.
 4. The apparatus according to claim 1,wherein the balloon is adapted to promote a feeling of satiety in thesubject.
 5. The apparatus according to claim 1, wherein the balloon isadapted to interfere with peristaltic waves and gastric emptying of thesubject.
 6. The apparatus according to claim 1, comprising a devicecoupled to the anchor, selected from the list consisting of: atherapeutic device, and a transmitting device.
 7. The apparatusaccording to claim 1, comprising a closure mechanism coupled to aproximal end of the inflation tube, configured to maintain pressurewithin the balloon by preventing leakage of fluid therefrom into thestomach of the subject.
 8. The apparatus according to claim 1,comprising an extraction tool configured to stretch the inflation tubeby reversibly engaging and pulling on the inflation tube.
 9. Theapparatus according to claim 1, comprising a filling tube configured tobe temporarily coupled to the inflation tube while the inflation tube isstretched, and configured to facilitate inflation of the balloon whenthe inflation tube is relaxed at least in part following beingstretched.
 10. The apparatus according to claim 1, wherein the anchorcomprises a resilient tube, and wherein the apparatus comprises abend-limiting tube coupled to the resilient tube, which limits an extentof bending of the resilient tube.
 11. The apparatus according to claim10, wherein the inflation tube is configured to be disposed within theresilient tube, the resilient tube permitting the inflation tube toassume a straight position, or to bend up to a predefined limit.
 12. Theapparatus according to claim 1, wherein the anchor comprises a materialthat has an elastic memory which biases the anchor towards assuming apre-selected bent configuration.
 13. The apparatus according to claim12, comprising a straightening rod, and wherein: the anchor has a distalend and an open proximal end; the anchor is shaped so as to define acentral core extending from the open proximal end toward the distal end;and the anchor is configured to be straightened from the pre-selectedbent configuration by insertion of the straightening rod in the centralcore.
 14. A method, comprising: inserting into a stomach of a subject agastric balloon in fluid communication with an inflation tube; assessingan inflation level of the balloon following insertion thereof; inresponse to identifying a need for inflation of the balloon, stretchingthe inflation tube while keeping the balloon within the stomach; andinflating the balloon following the stretching of the inflation tube.15. The method according to claim 14, wherein assessing the inflationlevel of the balloon comprises determining a level of weight loss of thesubject and correlating weight loss to the level of inflation of theballoon.
 16. The method according to claim 14, wherein inflating theballoon comprises injecting a fluid into the inflation tube while aproximal end of the inflation tube is outside of a body of the subject.17. The method according to claim 14, comprising temporarily couplingthe inflation tube to a filling tube following the stretching of theinflation tube, and wherein inflating the balloon comprises: allowing atleast a portion of the inflation tube to return to the stomach while thefilling tube is coupled to the inflation tube; and injecting a fluidinto the inflation tube via the filling tube while the portion of theinflation tube remains disposed within the stomach.
 18. The methodaccording to claim 14, wherein stretching the inflation tube comprisesextracting a proximal portion of the inflation tube from a mouth of thesubject.
 19. The method according to claim 18, wherein extracting theproximal portion of the inflation tube comprises stretching theinflation tube to at least 2.5 times a resting length thereof. 20.Apparatus for use in a stomach of a subject, the apparatus comprising ananchor, which comprises: a flexible tube, which, when in a relaxedposition, is shaped so as to define a generally planar base portion thatprevents the anchor from passing into a duodenum of the subject; and atleast two cross-bar elements having ends which are positioned in avicinity of the base portion, which cross-bar elements are configured tohelp maintain a shape of the base portion.
 21. The apparatus accordingto claim 20, wherein the anchor is configured to be positioned in anantrum of the stomach such that the anchor to some extent interfereswith natural antral contractions of the antrum.
 22. The apparatusaccording to claim 20, wherein the tube is shaped so as to define aproximal portion that projects away from a plane defined by the baseportion, and wherein the apparatus comprises a balloon coupled to theproximal portion of the tube.
 23. The apparatus according to claim 20,wherein the anchor comprises at least one sleeve that encloses one ofthe cross-bar elements.
 24. The apparatus according to claim 20, whereinthe cross-bar elements are shaped so as to define respective lumenstherethrough, and wherein the cross-bar elements comprise respectiveelastic coupling bands that pass through the respective lumens.
 25. Theapparatus according to claim 24, wherein two portions of each of thecoupling bands protrude from the respective cross-bar element, and arecoupled to the base portion at two respective points that areapproximately opposite one another on the base portion.
 26. Theapparatus according to claim 24, wherein the anchor is configured, whenstretched, to assume an elongated position in which the tube isgenerally straight, and in which the cross-bar elements are positionedapproximately parallel with the tube.